Hallux valgus, commonly known as a bunion, is a progressive structural deformity of the first metatarsophalangeal (big toe) joint, and one of the most frequently presenting conditions in foot and ankle practice. Severity, rate of progression, and appropriate management vary considerably between individuals, making accurate clinical assessment — not assumption based on appearance — central to the right course of treatment.

What is a bunion?

The medical term for a bunion, hallux valgus, describes a deformity in which the big toe drifts laterally toward the second toe while the first metatarsal bone shifts in the opposite direction. The resulting prominence at the inside edge of the foot — the feature most people recognise as "the bunion" — is not itself the primary problem. It is the visible consequence of a change in alignment at the joint, and often reflects deeper changes in forefoot mechanics, including the position of the sesamoid bones beneath the joint and, over time, the angle of the metatarsal bone itself.

This distinction matters clinically. Because the deformity involves the joint and underlying bone rather than a simple soft-tissue lump, treatment aimed only at the visible prominence — without correcting the underlying angular relationship between the first and second metatarsals — does not address the deformity and is prone to recurrence.

Symptoms

• A firm, bony prominence at the base of the big toe, on the inside border of the foot
• Pain or tenderness localised to the prominence, aggravated by enclosed or narrow footwear
• Inflammation of the overlying soft tissue (bursitis), with redness or swelling
• Progressive restriction of joint movement, including early degenerative change in longstanding cases
• Secondary deformity of the lesser toes, including overlap of the first and second toes and associated corns
• In advanced cases, transfer of load to the lesser metatarsals, producing pain across the broader forefoot
  
  

Causes and risk factors

Hallux valgus results from an interaction between inherited joint and ligamentous laxity and mechanical load. A family history is common, reflecting an inherited predisposition to instability at the first metatarsophalangeal joint and the joint immediately behind it. Once that instability is present, mechanical factors — footwear with a narrow toe box, and biomechanical conditions such as flatfoot deformity — can accelerate progression. Footwear is often assumed to be the primary cause; in practice, it more accurately acts on an underlying structural predisposition rather than causing the deformity in isolation.

How it is diagnosed

Clinical assessment begins with a detailed history — the duration and rate of progression of the deformity, the nature and location of pain, and the degree to which footwear and daily activity are affected. Examination assesses the flexibility of the deformity, range of motion at the joint, and any secondary lesser toe deformity or callus formation.

A weight-bearing X-ray is the standard imaging investigation, taken under normal load-bearing conditions rather than a non-weight-bearing position. Two angular measurements — the hallux valgus angle and the intermetatarsal angle — grade the deformity as mild, moderate, or severe. This grading determines whether non-surgical management remains appropriate, and if surgery is considered, which technique is best matched to the deformity.

Non-surgical management

Non-surgical measures are appropriate first-line management for mild to moderate deformity, and for intermittent rather than persistent symptoms. They do not correct the underlying bony deformity, but can meaningfully reduce load and friction over the joint and slow symptomatic progression:

• Footwear modification — a wider, deeper toe box reduces pressure over the prominence and is often the single most effective conservative measure
• Padding and toe spacers — reduce friction and irritation of the overlying soft tissue
• Orthotic devices — address biomechanical contributors, such as excessive pronation, that may accelerate progression
• Activity and load modification — where specific movements or activities provoke symptoms

These measures are an ongoing strategy rather than a fixed course of treatment, reassessed if symptoms progress.

When surgery is considered

Surgical correction is considered when pain or functional limitation persists despite appropriate non-surgical management, or when imaging shows a deformity progressing at a rate likely to compromise the joint further. The decision rests on symptoms, functional impact, and the hallux valgus and intermetatarsal angles on weight-bearing X-ray — not the size of the visible prominence. This is also the point at which surgical technique, matched to deformity grade, is determined.

Frequently asked questions

What causes bunions?

Hallux valgus arises from an inherited predisposition to instability at the first metatarsophalangeal joint, on which mechanical factors — including footwear and biomechanical conditions such as flatfoot deformity — then act to accelerate progression. Footwear alone is rarely the underlying cause.

What is the difference between a bunion and hallux valgus?

None — the terms describe the same condition. "Bunion" is the common name for the visible prominence; hallux valgus is the clinical term describing the underlying joint deformity that produces it.

Do all bunions need surgery?

No. Deformity grade, symptom severity, and rate of progression — not the presence of a bunion alone — determine whether surgery is appropriate. Many cases are managed effectively with non-surgical measures, particularly where the deformity is mild and symptoms are intermittent.